In recent years, with the development in humanity and convenience, touch panels and display panels or display devices with touch function become more and more popular. Based on different working principles, there are several kinds of touch panel, such as a resistive-type touch panel, a capacitive-type touch panel and an electromagnetic-type touch panel. The resistive-type touch panel and the capacitive-type touch panel can be operated directly with a hand. In the case that a stylus is adopted to write, it is difficult to accurately distinguish a touch of the hand from that of the stylus since the hand generally contacts the touch panel. The electromagnetic-type touch panel mainly includes a plurality of electromagnetic induction coils or antennas, arranged in an X-direction and in a Y-direction, and a positioning device (such as an electromagnetic stylus). The electromagnetic-type touch panel can accurately determine a position of the electromagnetic stylus even though the hand contacts the touch panel.
FIG. 1a is a schematic structural diagram of a conventional electromagnetic-type touch panel. As showed in FIG. 1a, the electromagnetic-type touch panel includes: first coils 11 (including 11-1, 11-2, 11-3 . . . and 11-48) arranged in an X-direction and extending in a Y-direction, and second coils 12 (including 12-1, 12-2, 12-3 . . . and 12-48) arranged in the Y-direction and extending in the X-direction. Generally, the first coils 11 and the second coils 12 are crossed with each other and are insulated from each other, and both of the first coils and the second coils are provided on a substrate (not shown in FIG. 1a). Taking the first coils 11 as an example and in conjunction with FIGS. 1b and 1c, a method for driving and detecting the conventional touch panel is described. After being applied with a drive signal and emitting an electromagnetic signal, each first coil receives an electromagnetic signal reflected by an electromagnetic stylus and generates an induction signal. The first coil 11-1 is applied with the drive signal and accordingly emits the electromagnetic signal. The electromagnetic stylus receives the electromagnetic signal emitted from the first coil 11-1. A resonance circuit (such as an LC resonance circuit) in the electromagnetic stylus generates an electromagnetic signal having a same frequency as the electromagnetic signal emitted by the first coil 11-1, and the electromagnetic stylus emits the generated electromagnetic signal. The first coil 11-1 generates an induction signal (which is generally an induced voltage) after receiving the electromagnetic signal emitted by the electromagnetic stylus. Similarly, each of the first coils 11-2, 11-3 . . . and 11-48 generates an induction signal. Therefore, 48 induction signals are generated. A function fitting (such as a quadratic function fitting) is performed on the 48 induction signals, and a value corresponding to a peak (Xp) of a fitted curve is taken as an X-direction coordinate of a touch position of the electromagnetic stylus.
With the foregoing touch panel and method for driving and detecting the touch panel, the touch position of the electromagnetic stylus may be well determined, while the detection efficiency needs to be improved.